One thing I love about paleo is the fact that there is no
single figure, like Atkins, who can define exactly what
the diet is. Rather, scientists can all propose what they
think our diet would have been 100,000 years ago, and in
fact it probably varied throughout the world, so there is
no single "Paleo Diet" that can be "owned" by anyone.

After this conversation, I came up with a couple of
"definitions" (some blatantly stolen from other contexts):

Deep paleo

Those who will only eat a pure paleo diet. No oil, no
vinegar, etc.

Neopaleo

People who basically eat a paleo diet, but also include
new things as long as they're not grain, or whatever. For
instance, wine, wine vinegar, salt, etc.

Fusion paleo

Those who try generally to eat a paleo diet but slip into
a neolithic diet when they so desire, adding cake or
french fries or whatever at times.

Jens Wilkinson